Cupra random misfires only at idle!

Feb 9, 2019
11
1
Hello there I have recently purchased a lovely 2008 Cupra with the BWJ engine code!

I noticed at idle when the car is warm it will randomly pop out the exhaust whilst misfiring and you can feel these jerks in the car!

I have been to the garage vcds said cylinder 2 misfiring and bank1 too lean which is the first exhaust sensor, this was broken by the mechanic when I got a custom downpipe installed as it was so stuck (Havent changed that yet)

Changed plugs and coils still doing it.

Compression test was also done, this resulted in the same compression on all 4 cylinders.

(Suspected leaking injector)

Got the injectors cleaned and tested they was fine still almost flowing like new and all seals replaced, also had a carbon clean!

STILL DOING IT!

Oh and i removed the metal inserts from inside the head as one of them had snapped in half from excessive carbon build up!
Must of been very lucky tbh!
Left the manifold flap in so I don’t get a code pop up! So no worries there.

I have heard the horror stories of people’s engines failing due to a dodgy injector with the same symptoms as what I have now!

Also I would like to add if I rev the engine with the clutch in whilst driving (rolling) the revs don’t seem to drop instantly,

this also happens when changing gear sometimes so it bites on the clutch in the next gear harder than it should as the revs are not falling as fast as they should whilst shifting. (Feels that way to me) (Very annoying)

Am hoping there is an air leak somewhere but I can’t find anything I’ve looked all over even underneath!

Car also has new thermostat as old one wasn’t staying at 90 but now that’s perfect.

Also new camshaft sensor.

If anyone has any ideas maybe something that could help then please send me a message :)

Thanks allot..... Dan
 
Feb 9, 2019
11
1
Here is a picture of the broken piece
 

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